1. Field of the Invention
This invention relates to a photovoltaic device for converting optical energy into electric energy and more particularly to a photovoltaic device composed mainly of an amorphous semiconductor film.
2. Description of the Prior Art
It is known that a photovoltaic device can be composed mainly of a photoelectrically active layer of a hydrogenated amorphous semiconductor containing silicon. Such a device can be manufactured with its larger area at a lower cost and thus it is preferable for a large-scaled solar battery. However, it is also known that the photoelectric conversion efficiency of the photovoltaic deivce of hydrogenated amorphous semiconductor is lower than that of a photovoltaic device of crystalline semiconductor and it is degraded after intense light irradiation for a long time (refer to the Japanese patent Laying-Open Gazette No. 59-54274).